This invention relates to a process for reacting a phenol with an epoxy-containing compound. More particularly, the invention provides a process for increasing the molecular weight of an epoxide by reacting the epoxide with a phenol in the presence of certain "hard cation/non-nucleophilic anion" catalysts, preferably in the presence of a base.
The preparation of higher molecular weight epoxy resins via the so-called fusion technique wherein a lower molecular weight epoxy compound is reacted with a phenol in the presence of a suitable esterification catalyst is well known. See, for example, U.S. Pat. No. 3,477,990, which is directed to precatalyzed polyepoxides containing phosphonium halides and to their reaction with phenols.
It is also known that the polyepoxide/phenolic reaction can be catalyzed by phosphines as disclosed in U.S. Pat. No. 3,547,881 and by potassium iodide as disclosed in U.S. Pat. No. 3,978,027.
While all of these fusion compositions and processes are commercially useful, each has its own shortcomings. Accordingly, there is a continuing need to find other alternative processes, especially alternative catalysts systems.